<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <!--
    :nth-child(index)
        :first-child
        :last-child
        :nth-last-child(index)
        :only-child(相当于:first-child:last-child
            或nth-child(1):nth-last-child(1))
    :nth-of-type(index)
        :first-of-type
        :last-of-type
        :nth-last-type(index)
        :only-of-type(相当于:first-of-type:last-of-type
            或nth-of-type(1):nth-last-type(1))

    :empty 内容是空的，可以由属性
    :not
    -->
    <style>
        * {
            margin: 0;
            padding: 0;
        }
        #wrap li:nth-child(1) {
            color: pink;
        }
    </style>
</head>
<body>
    <ul id="wrap">
        <li>1</li>
        <li>2</li>
        <li>3</li>
        <li>4</li>
        <li>5</li>
        <li>6</li>
        <li>7</li>
        <li>8</li>
    </ul>
</body>
</html>
